2005-04-16 18:46:19

by Paul Ionescu

[permalink] [raw]
Subject: hot-addacpi-hotplug-decouple-slot-power-state-changes-from-physical-hotplug.patch

--- Rajesh Shah <[email protected]> wrote:

> > Is p2p hotplug in your roadmap (for i386) ?
>
> I believe others are already working on it. I expect to free up
> a bit more in a couple of weeks. If I don't see any patches or
> indication of activity by then, I'll work on adding this support
> too.
>
> Rajesh

Hi Rajesh,

While waiting for a p2p bridge hotplug support, I give a try to linux-2.6.12rc2-mm3 which include
your patch for powering on and off an ACPIPHP controlled PCI slot without actually remove the pci
card.
I gave it a try on my IBM thinkpad booted in docking station which has an ACPIPHP slot.

An echo 0 > /sys/bus/pci/slots/SOME_NUMBER/power is removing some devices ( verified with cat
/proc/pci ), but gives some kernel errors on console.
An echo 1 > /sys/bus/pci/slots/SOME_NUMBER/power is not activating the devices again ( again
tested with cat /proc/pci) but gives some kernel errors on console + some cpu registers and a
segfault.

In my dock I have a ide controller, 2 yenta pcmcia slots, and a PCI slot where I have a bttv
supported tv card.
All drivers needed were compiled in kernel, no modules needed.

Was this setup supposed to work ?
I can provide more info if needed.

Thanks,
Paul






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2005-04-18 23:28:17

by Rajesh Shah

[permalink] [raw]
Subject: Re: hot-addacpi-hotplug-decouple-slot-power-state-changes-from-physical-hotplug.patch

On Sat, Apr 16, 2005 at 11:46:13AM -0700, Paul Ionescu wrote:
>
> Was this setup supposed to work ?
>
Not yet, sorry. This patch was simply decoupling the power state
of the device from its physical presence in the slot. It had
nothing to do about programming p2p bridges and subordinate
devices correctly.

I know some folks from Fujitsu are working on this and should
be sending out patches shortly. Not sure if these will support
docking stations fully but even if they don't, we'll have a better
starting base to build on.

Rajesh